不同方法制备钴铈复合氧化物催化剂的性能和表征

以共沉淀法和球磨法制备了钴铈复合氧化物催化剂，考察了其对对甲酚液相氧化选择得到对羟基苯甲醛的催化性能用ＸＲＤ方法对其结构进行了表征。结果表明；球磨法制备的Ｃｏ／Ｃｅ＝１的钴铈复合物活性和比活性最高，收醛选择性达８１．８％，具有工业应用前景。共沉淀法制备的钴铈复合氧化物的催化性能随处理温度的升高而逐渐改善，证实了氢氧化物为非活性物相，而氧化物物相对液相碱助反应体系是适宜的。     

钴锰掺镝复合催化剂的制备与性能研究

通过掺合稀土元素镝对钴锰催化剂的性能进行改性,并在料液中加入明胶进行超声水热处理,然后通过TG-DSC、SEM、XRD、甲烷催化燃烧试验等方法对前驱体及复合催化剂的结构和性能进行表征,结果表明:催化剂颗粒内部孔洞密布,有较大的比表面,其催化活性比改性前的催化剂提高约75%。     

不同方法制备钴铈复合氧化物催化剂的性能和表征

以共沉淀法和球磨法制备了钴铈复合氧化物催化剂,考察了其对对甲酚液相氧化选择得到对羟基苯甲醛的催化性能,用XRD方法对其结构进行了表征.结果表明:球磨法制备的Co/Ce=1的钴铈复合氧化物活性和比活性最高,收醛选择性达81.8%,具有工业应用前景.共沉淀法制备的钴铈复合氧化物的催化性能随处理温度的升高而逐渐改善,证实了氢氧化物为非活性物相,而氧化物物相对液相碱助反应体系是适宜的.     

镧铈复合氧化物修饰的Cu-Co合金催化剂用于合成气直接制乙醇

Cu-Co双金属的结构和组成决定了其催化合成气直接制乙醇的性能。通过柠檬酸络合辅助的等体积浸渍法制备了ZrO₂负载的钙钛矿型复合氧化物La_0.95Ce_0.05Co_0.7Cu_0.3O₃,经原位还原,得到了La-Ce-O掺杂的ZrO₂担载的Cu-Co双金属催化剂。结果表明,催化剂中活性组分以Cu-Co合金的形式存在,且Cu-Co合金高度分散于载体表面,而La-Ce-O以复合氧化物的形式存在。该催化剂用于合成气直接制乙醇,在温度为280℃,压力为4 MPa,空速为3 900 mL·（g·h）^-1,V（H₂）∶V（CO）∶V（N₂）=8∶4∶1的反应条件下,CO转化率为9%,总醇的选择性为29.7%,总醇中乙醇的选择性为63.5%,具有优良的催化性能。     

负载型锰铈复合氧化物SCR脱硝催化剂制备研究

采用复壁炭纳米管(CNTs)为载体,通过室温氧化还原法制备了锰铈复合氧化物低温NH_3-SCR脱硝催化剂Mn-CeO_x/CNTs。通过调节浸渍液的组成,考察了活性分锰铈配比对催化剂低温脱硝性能的影响。研究发现锰铈协同作用能够有效提高催化剂的低温脱硝性能,当Mn/(Ce+Mn)的摩尔比为0.6时,催化剂的低温活性最好,反应温度为160～180℃时脱硝率可达100%。该方法具有制备工艺简单、条件温和、低温脱硝效果好等优点。     

铈锆复合氧化物制备方法进展

CexZr1-xO2具有良好的抗高温老化性能、低温还原性能及较高的储氧能力,可作为新一代三效催化剂的关键材料.本文较为全面的综述了铈锆复合氧化物各种制备方法进展.     

钴铈复合氧化物催化降解2,4,6-三氯酚

采用溶胶-凝胶法制备了一种疏松多孔的钴铈复合氧化物,该复合氧化物具有较大的比表面积和孔体积。并以废水中一定浓度的2,4,6-三氯酚作为模型化合物,研究自制的钴铈复合氧化物对水中的2,4,6-三氯酚的催化降解效果。研究结果表明,自制的钴铈复合氧化物所具有的氧化还原性能以及协同催化作用使其对废水中的2,4,6-三氯酚具有一定的催化降解活性。初始溶液的pH值对降解影响较大,酸性条件更有利于2,4,6-三氯酚的降解。100 mg自制的钴铈复合氧化物与10 mL 100 mg/L的2,4,6-三氯酚在25℃下恒温振荡30 h,2,4,6-三氯酚的降解率可达到86.3%,溶液中可被氧化的有机物含量下降了36.7%。     

铜掺杂Zr0.4Ce0.6O2复合氧化物催化剂性能的研究

研究了铜掺杂Ｚｒ０．４Ｃｅ０．６Ｏ２复合氧化物的还原性和催化性能,结果表明,铜掺杂能显著提高昨合氧化物中氧化铈的还原性,降低氧化铜的还原温度,也能提高对ＣＯ氧化的催化活性和催化 这说明在铜与锆铈复合氧化物之间存在较强的相互作用,焙地催化剂样品的性能亦有一定影响。     

铈调变钙钛矿型氧化物催化剂的研究进展

介绍了钙钛矿型氧化物(可用通式ABO3来表示)的典型正交晶体结构,简单分析了稀土铈调变钙钛矿型氧化物催化剂性能与结构的关系,概述了铈调钙钛矿型氧化物催化材料在催化氧化、汽车尾气治理、电催化和一些其他方面的研究进展。     

Iron catalyst for ammonia synthesis doped with lithium oxide

Iron catalysts doped with Al₂O₃, CaO were obtained by melting iron oxide with 2.2 wt.% of Al₂O₃, 2.1 wt.% of CaO. The reduced catalyst was impregnated with lithium hydroxide water solution. Activity measurements were carried out in the laboratory installation in the temperature range 623–773 K under the pressure of 10 MPa. The activity of catalyst containing 0.79 wt.% of Li₂O and reduced at 773 K was similar to the activity of an industrial iron catalyst doped with potassium oxide. After reduction at 923 K the catalyst containing 0.48 wt.% of Li₂O was about 15% more active than the industrial catalyst. Increasing Li₂O concentration results in the decrease of the surface area of a catalyst reduced at 923 K. The most active catalysts doped with lithium oxide were more active than the industrial catalyst when their activity was calculated and scaled down to surface area units.     

丙烯选择性氧化催化剂性能

通过分步沉淀法制备Mo-Bi-Co-Ni-Fe-K-O复合氧化物催化剂,考察了反应温度、空速和氧烯比等条件对丙烯氧化制备丙烯醛反应中催化性能的影响.结果表明,在反应温度(325～330)℃、空速(1 300～1 700)h-1和n(O2):n(C3H6)=1.5～1.7条件下,丙烯转化率98%,目的产物收率94%.经5...     

镍硅改性对环氧乙烷合成用银催化剂及其载体性能的影响

氧化铝原料来源改变后,银催化剂活性和稳定性波动,为了改善银催化剂性能,分别对载体进行硅改性、镍改性及镍硅共同改性。采用X射线衍射、N2物理吸附-脱附、压汞和扫描电镜等对催化剂物性及微观结构进行表征,研究各种改性对载体孔结构、比表面积和强度等的影响。结果表明,经各种改性后载体的小孔增多,比表面积增大,载体强度增加。制成的银催化剂在空速6 000 h-1和出口环氧乙烷物质的量分数为2.50%条件下进行微反评价,银催化剂的活性和稳定性均提高,其中,以镍硅共同改性后的效果最佳,运行至第215天时,反应温度仅为231.7℃,而未改性催化剂运行至第8天时,反应温度已达227.0℃。     

氧化物催化剂上石脑油催化裂解制乙烯的研究

使用固定流化床,考察了氧化物催化剂催化裂解石脑油制乙烯的反应。研究结果表明,温度、空速和水油比对裂解产物分布有直接影响。在反应温度700 ℃、空速0.75 h^－1和水油质量比3∶1条件下,得到最大的乙烯收率为32.93%。     

对合成催化剂配体金属有机化合物的研究

完成了金属镁及有机化合物配置合成催化剂配体的方式,并且分析及介绍了两者的反应。金属离子在出现金属化合反应之后,能够取代有机化合物中的的氢原子。碳负离子反应是金属化合物及有机化合物能够出现化学反应,基于此特性,对此种化合物制备过程中的条件进行了分析,从而为不对称有机化学反应催化剂制备过程中提供基础。     

铝化合物催化聚酯缩聚研究

以5种铝化合物为催化剂,采用DMT路线合成聚酯,对聚合产物进行特性粘数、色值和DSC测试,结果表明: 铝化合物的催化活性略低于Sb2O3,聚酯b值也有所增加。选择溶解性好的铝化合物和减少催化剂用量对增加活性和改善 聚酯色相有利。     

Direct synthesis of dimethyl carbonate over rare earth oxide supported catalyst

Solid base catalysts for the direct synthesis of dimethyl carbonate (DMC) from carbon dioxide, methanol, and propylene oxide were prepared by loading KCl and K₂CO₃ on the surface of La₂O₃, Y₂O₃, CeO₂ and Nd₂O₃. The catalysts were characterized by thermogravimetric analysis (TGA) and X-ray diffraction (XRD) techniques. The catalytic activities were efficiently influenced by the preparation conditions. The optimal loading amount of K₂CO₃ is 17.6% (mass) for KCl-K₂CO₃/Y₂O₃ and 22.2% for other catalysts. Supports affected the activity of catalyst. KCl-K₂CO₃/Nd₂O₃ exhibited the highest activity. The activity of KCl-K₂CO₃/Y₂O₃ increased with the increase of calcination temperature in the range of 800°C–900°C. The formation of KYO₂, Y₃O₄Cl or YO_X species probably promoted the catalysts. Translated from Natural Gas Chemical Industry, 2006, 31(1): 39–43 [译自: 天然气化工]     

Influence of catalyst structure on direct ethoxylation of fatty methyl esters over Al-Mg composite oxide catalyst

During direct ethoxylation of fatty methyl ester over Al-Mg composite oxide catalyst, the activity was nearly proportional to the total number of active Al acidic sites on the catalyst surface per unit weight of catalyst. Lower active Al acidic site densities resulted in a narrower ethylene oxide (EO) adduct distribution of obtained ethoxylate. We developed a new catalyst with a large surface area on which many acidic sites are distributed uniformly by partially poisoning the Al acid sites of high-Al content Al-Mg composite oxide with alkali. This catalyst was used for direct ethoxylation of fatty methyl esters to obtain ethoxylated fatty methyl esters with narrow EO adduct distribution efficiently.     

复合氧化物Nd2O3/SnO催化合成阿斯匹林

本文以水杨酸和乙酸酐为原料,以Nd2O3/SnO为催化剂,合成了阿斯匹林。并考察了催化剂种类及用量、反应温度、反应时间和醇酸摩尔比对产物产率的影响。实际结果表明,Nd2O3/SnO是合成阿斯匹林的良好催化剂,最佳工艺条件为水杨酸与乙酸酐摩尔比为1∶3,反应时间0．5h,反应温度80－86℃,催化剂用量为水杨酸质量的5％。在此条件下,阿斯匹林产率达70％。     

Selective oxidation of toluene ando-xylene on MgF2-supported monolayer vanadium oxide catalyst

Information on the reactions of selective oxidation of toluene ando-xylene on monolayer V₂O₅/MgF₂ catalyst was obtained using IR spectroscopy. Also adsorption of aldehyde derivatives of these reagents, i.e. benzaldehyde ando-tolualdehyde, was investigated in order to identify intermediate species, which were formed during the oxidation process. The measurements were carried out at different temperatures, under conditions similar to that of the catalytic reaction. On the surface of the catalyst many intermediate species, as aldehyde-like, keton-like and benzoate species, were detected. On the basis of the data obtained the mechanism of these reactions has been proposed.